A substrate processing system including a single type substrate processing apparatus has been known. This type of system may include a substrate processing apparatus that holds a substrate which has a film formed on its surface, rotates the substrate around a vertical axis, and supplies a processing liquid from a nozzle to a peripheral edge portion of the substrate to thereby remove the film at the peripheral edge portion of the substrate. Hereinafter, the substrate processing apparatus will be referred to as a first substrate processing apparatus. In Japanese Patent Laid-Open Publication No. 2013-168429, an imaging mechanism is provided in the substrate processing system to capture an image of the peripheral edge portion of the substrate processed by the first substrate processing apparatus, and based on the captured image, it is determined whether the film of the peripheral edge portion is properly removed. Meanwhile, apart from the first substrate processing apparatus, there is known a substrate processing apparatus including an enclosure member that holds a peripheral edge portion of a substrate from a lower side and surrounds the whole peripheral edge portion of the substrate, and processes the substrate held by the enclosure member. Hereinafter, the substrate processing apparatus will be referred to as a second substrate processing apparatus. See, for example, Japanese Patent No. 5372836.